Cuff Electrode with Soft Edges for Tissue Protection
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Solution Overview
Problem
Cuff electrodes and optrodes for implantable medical devices often cause compression injuries and tissue damage due to pressure peaks at the edges, leading to nerve blood flow impairment, demyelination, and axonal degeneration, while also experiencing issues with stray currents and virtual electrode formation.
Innovation Solution
The design features a cuff electrode/optrode with a support sheet that forms a tubular or helical structure with soft edge portions, where the mean edge thicknesses are lower than the central thickness, and the inner surface extends beyond the central outer surface, reducing pressure on the tissue and minimizing current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cuff electrode uses a uniform thickness design, then the manufacturing is simple, but pressure peaks occur at the edges causing tissue damage
Solution Approach 1:
The cuff electrode employs variable thickness design where the edge portions have reduced thickness compared to the central portion. This local variation in geometric properties softens the edges to reduce pressure peaks on the tissue while maintaining structural integrity in the central region, directly resolving the contradiction between manufacturing simplicity and tissue protection.
2Strength
If the cuff electrode has thick edges for structural support, then the mechanical strength is improved, but compression injuries and nerve damage occur
Solution Approach 1:
The design distributes structural support functions to the central portion with greater thickness while reducing edge thickness to minimize compression injuries. This local differentiation allows the cuff to maintain overall structural integrity without transmitting excessive pressure to the tissue at the edges.
3Ease of manufacture
If the cuff electrode uses straight edges, then the manufacturing is easier, but stray currents and virtual electrode formation increase
Solution Approach 1:
Instead of using straight edges that create sharp discontinuities, the invention inverts the approach by using bevelled or rounded edges that create gradual transitions. This geometric inversion eliminates the sharp boundaries that generate virtual electrodes and stray currents, while the bevelled edges remain manufacturable with standard techniques.
4Object-affected harmful factors
If the cuff electrode uses bevelled edges to reduce pressure, then tissue damage is reduced, but the manufacturing complexity increases
Solution Approach 1:
The invention modifies the geometric parameters of the edge portions by reducing thickness and applying bevels, which can be achieved through standard manufacturing processes like laser cutting or precision machining. These parameter changes effectively reduce tissue damage while maintaining manufacturing feasibility within existing technological capabilities.
Data Source
AI summary
An implantable cuff electrode and/or optrode (40) adapted to encircle a substantially cylindrical tissue (70), is provided that includes a support sheet (43) rolled about a longitudinal axis, forming a cuff of inner diameter, Dc, and extending over a length, L a central portion, extending over a length, lc, of at least 50% of the length, L, and having a mean central thickness, tc, and wherein the central portion is flanked on either side by, a first edge portion (43e) of mean edge thickness, te1, and a second edge portion (43e) of mean edge thickness, te2, at least a first electrode contact or a first optrode exposed at an inner surface of the cuff, and remote from an outer surface forming the exterior of the cuff, Characterized in that, the mean edge thicknesses, te1, te2, of the first and second edge portions are each lower than tc.